1. Field of the Invention
The present invention generally relates to a method of and an apparatus for assembling sliders and particularly a method of and an apparatus for joining a slider body and a pull tab diecasted separately from each other.
2. Description of the Prior Art
Japanese Patent Publication No. 1-25563 discloses a conventional slider-assembling apparatus of the type described above. The conventional apparatus comprises a pair of juxtaposed slant chutes, the first chute for feeding a series of slider bodies from a slider body hopper to one end of a horizontal transport path and the second chute for feeding a series of pull tabs from a pull tab hopper to a position above the transport path a little ahead of the path end. The leading slider body rests flat on the transport path with its attachment lug opened forwards, while the leading pull tab hangs at the end of the second chute via its own weight with its attachment aperture directed downwards ready to be caught by the opened lug of the slider body. The leading slider body is pushed forwards by a pusher horizontally along the transport path, thus causing the distal end of the attachment lug on the slider body to catch the aperture of the leading pull tab hanging from above. The slider body continues to advance until it stops at a slider-assembling station, where, an anvil member advances along the transport path from its opposite end, to intrude into the slider body. At this instant, a presser rod descends to press down the distal end of the attachment lug to thereby confine the aperture of the pull tab to the attachment lug, so that the pull tab is pivotally joined to the attachment lug on the slider body. Thereafter, the anvil member retracts from the assembling station while holding the assembled slider thereon and then discharges the assembled slider through a withdrawal exit of the apparatus.
Although this conventional assembling apparatus proves to be satisfactory to some extent, it suffers from several disadvantages. Since a pull tab is merely hanging before the slider assembling station, the pull tab is prone to be laterally displaced from the path of the attachment lug of the slider body. If the slider body is pushed forwards by the pusher in this disposition, the attachment lug fails to catch the aperture of the pull tab, and the pull tab can not be joined to the slider body.
Since the aperture in the pull tab varies in shape, size and position; the attachment lug must be spread apart from the upper surface of the slider body as widely as possible in order to assuredly catch the various apertures of the hanging pull tab. Since the attachment lug is spread apart so widely, closing the attachment lug for joining the pull tab to the slider body causes the lug to be subjected to severe deformation, so the attachment lug is more likely to break or be damaged.
Furthermore, there are problems that two slider bodies are inclined to be erroneously transported at the same time by a pusher and that the front end of the pusher is apt to be jammed into the preceding horizontal slider body and the ensuing inclined slider body. These problems result in the apparatus becoming inoperative. Consequently, smooth transportation of the slider body from the chute to the slider-assembling station cannot be accomplished.